In nuclear power plants, plant outages are performed for the structure thereof. Appropriate repair is performed for a part where it is considered that repair is required according to the plant outage. Thus, in nuclear power plants, operations such as plant outages and repair are required to maintain normal operating conditions. In such operations, it is necessary to reduce an amount of radiation to workers.
Taking this necessity into account, there can be considered an installation of a wall-shaped shielding material that shields radiation in a structure, which is an object to be shielded. However, to reduce the amount of radiation, a shielding material having a weight of, for example, 100 kilograms or more is required. It is not easy to transport such a heavy shielding material to a checking location or a repair location. Further, there is an idea that the shielding material can be divided into pieces of about 10 kilograms; however, because a long installation time is required in a higher or narrower location, there is a concern about exposure to radiation of workers at the time of installing the shielding material.
Conventionally, for example, Patent Literature 1 discloses a pipe cleaning method in which a cleaning area and a non-cleaning area of a pipe are isolated from each other by simple means. According to this cleaning method, a balloon is inserted into a boundary between the cleaning area and the non-cleaning area of the pipe, air or fluid such as water is supplied into the balloon to pressurize the balloon, thereby isolating the cleaning area of the pipe from the non-cleaning area.
That is, it can be considered to apply the conventional cleaning method at the time of performing a plant outage or repair of a nuclear power plant, in which radiation is easily shielded by a shielding body in which water is filled in a balloon, thereby reducing the amount of radiation to a worker.